ping Command

Router#ping w.x.y.z	Checks for Layer 3 connectivity with device at address w.x.y.z
Router#ping	Enters extended ping mode, which provides more options

The following table describes the possible ping output characters.

Character	Meaning
!	Successful receipt of a reply
.	Device timed out while waiting for reply
U	A destination unreachable error PDU was received
Q	Source quench (destination too busy)
M	Could not fragment
?	Unknown packet type
&	Packet lifetime exceeded